Stress control brush

ABSTRACT

A stress control brush includes a brush head, an elastic plate and a handle. The brush head includes a bristle seat and a first limit part. The handle includes a holder and a second limit part. The elastic plate connects the brush head and the handle. The elastic plate with curved structure has an unbending type and a collapsed bending type. The first limit part and the second limit part are pressed against each other so as to restrict the bending curvature of the elastic plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 103133642 filed in Taiwan, R.O.C. on Sep. 26, 2014, the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to a brush, more particular to a stress control brush.

BACKGROUND

Good teeth brushing habits help people to maintain oral hygiene and avoid tooth decay. In order to keep oral hygiene, people brush their teeth everyday with a strong force hoping to prevent their teeth from decay. However, according to a report, researchers pointed out that when teeth are brushed too hard, the surface of the teeth and the gums would become damaged, increasing the risk of having decay and periodontal disease.

U.S. Pat. No. 5,146,645 discloses a tooth brush which can signal the user that a predetermined brushing force has been exceeded. The tooth brush includes a resilient twin beam structure connecting the brush head and the handle. During normal use, the back side beam is subjected to compressive stress whereas the face side beam is subjected to tensile stress. When a predetermined force is exceeded, the back side beam resiliently buckles and inverts to a downwardly convex arch configuration that makes the brush deflect significantly. When the excessive force is removed, the back side beam returns to its original position by the resilient of itself. When a force exceeding the predetermined force is applied to the substantial deflected brush, the deflection of the tooth brush is increased and the tooth brush loose its function so as to avoid hurting the teeth and gum tissue.

U.S. Pat. No. 6,327,734 discloses a sensing and signaling system for tooth brushes which reminds the user that the stress applied to the teeth has exceeded a critical value. The sensing and signaling system comprises a hinged member that is fixedly attached to a brush-head body. An arm member is attached at one end to said hinged member and pivots about a hinge portion of the hinged invention. The pivoting arm member and the brush-head member nestle within the toothbrush body. The brush-head member comprises a striking element portion that extends away from a rear surface of the brush-head. Mounted on the toothbrush body beneath the brush-head member is a collapsible and recoverable dome member, which provides an alarm indication by collapsing when excessive pressure is applied by the user to the brush-head against the teeth. When the excessive pressure is removed, the dome member recovers to the original shape and pushes the brush-head member back to the original position.

Although the tooth brushes described above are capable of notifying users whether or not the stress applied to teeth during brushing hurts teeth and gums, some problems exist when users use the tooth brushes described above. The tooth brush disclosed in U.S. Pat. No. 5,146,645 has a problem that when the stress exceeds a predetermined value, the brush is deflected significantly, even being temporarily disabled. Therefore, the tooth brush is not able to clean the particularly dirty parts of the teeth with excessive force. For example, the residue between teeth is not able to be cleaned up by the tooth brush with a force stronger than the critical force. In addition, the tooth brush disclosed in U.S. Pat. No. 6,327,734 has complicated structures and mechanisms of force transfer. When users brush their teeth with this kind of brush, the trigger stress causing the deformation of the brush may be different each time. Moreover, residue are easily kept inside the brush head. Bacteria significantly grow when the environment is too humid such that this brush easily becomes moldy, which increases the possibility of inflection.

SUMMARY

According to one embodiment of the present disclosure, a stress control brush comprises a brush head, a handle and an elastic plate. The brush head comprises a bristle seat and a first limit part. The handle comprises a grip and a second limit part. The elastic plate interconnects the brush head and the handle. The elastic plate with a curved structure has an unbending state and a collapsed bending state. Wherein, the first limit part and the second limit part press against each other so as to restrict a bending curvature of the elastic plate at the collapsed bending state.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description given herein below, along with the accompanying drawings which are for illustration only, thus are not limitative of the present disclosure, and wherein:

FIG. 1 is a schematic perspective view of a brush according to a first embodiment of the present disclosure;

FIG. 2A is an exploded view of the brush according to the first embodiment of the present disclosure;

FIG. 2B is a schematic perspective view of an elastic plate of the brush according to the first embodiment of the present disclosure;

FIG. 3A and FIG. 3B are cross-sectional views of the brush according to the first embodiment of the present disclosure;

FIG. 4 is a schematic perspective view of a brush according to a second embodiment of the present disclosure;

FIG. 5 is an exploded view of the brush according to the second embodiment of the present disclosure;

FIG. 6A is a cross-sectional view of the brush according to the second embodiment of the present disclosure;

FIG. 6B is a cross-sectional view of an elastic plate of the brush along a line 6B-6B in FIG. 6A according to the second embodiment of the present disclosure;

FIG. 7 is a schematic perspective view of a brush according to a third embodiment of the present disclosure;

FIG. 8 is an exploded view of the brush according to the third embodiment of the present disclosure;

FIG. 9A to FIG. 9C are cross-sectional views of the brush according to the third embodiment of the present disclosure;

FIG. 10A to FIG. 10C are front side views of brushes according to the fourth to sixth embodiments of the present disclosure; and

FIG. 11A to FIG. 11B are cross-sectional views of brushes according to the seventh and eighth embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings.

Please refer to FIG. 1 to FIG. 3B. FIG. 1 is a schematic perspective view of a brush according to a first embodiment of the present disclosure. FIG. 2A is an exploded view of the brush according to the first embodiment of the present disclosure. FIG. 2B is a schematic perspective view of an elastic plate of the brush according to the first embodiment of the present disclosure. FIG. 3A and FIG. 3B are cross-sectional views of the brush according to the first embodiment of the present disclosure.

The first embodiment of the present disclosure discloses a brush 100 which comprises a brush head 110, an elastic plate 120 and a handle 130. The brush head 110 comprises a bristle seat 111, a plurality of bristles 112 and a first limit part 113. The bristle seat 111 has a front surface 1111, a back surface 1112 and two side surfaces 1113. The front surface 1111 and the back surface 1112 are opposite to each other. The two side surfaces 1113 are opposite to each other and located between the front surface 1111 and the back surface 1112. The plurality of bristles 112 is located on the front surface 1111 of the bristle seat 111. The first limit part 113 is located on the back surface 1112 of the bristle seat 111. The bristle seat 111, the plurality of bristles 112 and the first limit part 113 are made of polymer. However, the disclosure is not limited to the composition of the bristle seat, the plurality of bristles and the first limit part.

The elastic plate 120 is a rectangle elastic plate with curved shape. However, the disclosure is not limited to the foregoing planar shape of the elastic plate. Moreover, the elastic plate 120 has a convex 124, a concave 125, a first arc side 121, a second arc side 122 and two straight sides 123. The convex 124 and the concave 125 are opposite to each other. The first arc side 121 and the second arc side 122 are opposite to each other. The two straight sides 123 are opposite to each other and located between the first arc side 121 and the second arc side 122. The direction of a connecting line between the midpoint of the first arc side 121 and the midpoint of the second arc side 122 is parallel to the direction of a connecting line between the brush head 110 and the handle 130. The first arc side 121 of the elastic plate 120 is connected to the bristle seat 111. The concave 125 of the elastic plate 120 and the front surface 1111 of the bristle seat 111 both face the same direction.

The handle 130 comprises a grip 131 and a second limit part 132. One end of the grip 131 is connected to the second arc side 122 of the elastic plate 120. The second limit part 132 is located on a side surface of the grip 131 which is facing the same direction with the convex 124 of the elastic plate 120. The grip 131 and the second limit part 132 are made of polymer. However, the disclosure is not limited to the composition of the grip and the second limit part.

In this embodiment, the first limit part 113 is a rib, and the second limit part 132 is a block. However, the disclosure is not limited to the shapes and configurations of the first limit part and the second limit part. The first limit part 113 extends from the bristle seat 111 toward the second limit part 132. Therefore, the first limit part 113 and the second limit part 132 can be pressed against each other when the brush head 110 is bent relative to the handle 130. In other embodiment of the present disclosure, the first limit part and the second limit part are a rib and a blocking plane, a block and a rib, or a blocking plane and a rib, respectively.

As shown in FIG. 1, FIG. 3A and FIG. 3B, when the brush 100 is not in use, which means no force is applied to the elastic plate, the elastic plate 120 is at an unbending state which the elastic plate 120 has no bending deformation. When the user is brushing their teeth, the brush head 110 applies a force on the teeth through the plurality of bristles 112. At the same time, the teeth also apply the first force F1, which has the same magnitude and the opposite direction with the force applied to the teeth, to the brush head 110 (namely, reactive force) so that the brush head 110 is bent relative to the handle 130. Assuming that the first force F1 is applied to the center point of the plurality of bristles 112 on the brush head 110 when the user brushes the teeth, the first force F1 takes the center point of the elastic plate 120 as the fulcrum and generates a pressing torque relative to the handle 130. Accordingly, the elastic force (a reactive force of the first force F1) of the elastic plate 120 takes the center point of the elastic plate 120 as the fulcrum and generates a resisting torque relative to the handle 130. When the applied force is fixed, the magnitude of the pressing torque is proportional to the distance between the center point of the plurality of bristles 112 and the center point of the elastic plate 120, and the resisting torque is proportional to a half of the length of the elastic plate 120 (the distance between the arc side of the elastic plate 120 and the center point of the elastic plate 120). The first force F1 applied to the brush head 110 which has a magnitude that equals a maximum magnitude of the elastic force provided by the elastic plate 120 as the reactive force is defined as the first critical force.

The curved structure of the elastic plate 120 provides higher anti-bending ability than the plane structure of the elastic plate. Therefore, when the first force F1 is weaker than or equal to the first critical force, the pressing torque generated by the first force F1 equals to the resisting torque generated by the elastic force of the elastic plate 120. The elastic plate 120 with the curved structure is at a trace bending state which the bending deformation of the elastic plate 120 is negligible. However, once the first force F1 is stronger than the first critical force, the resisting torque generated by the elastic force of the elastic plate 120 is smaller than the pressing torque generated by the first force F1. The curved structure of the elastic plate 120 collapses and looses high anti-bending ability. Therefore, the elastic plate 120 with the curved structure is at a collapsed bending state which the bending deformation of the elastic plate 120 is significant.

For example, when a user applies a proper force for tooth brushing, the first force F1 is weaker than the first critical force so that the elastic plate 120 is at the trace bending state which the bending deformation of the elastic plate 120 is negligible. Once the user applies an improper force, which can damage the teeth and the gums, for tooth brushing, the first force F1 is stronger than the first critical force so that the elastic plate 120 is at the collapsed bending state which the bending deformation of the elastic plate 120 is significant. Accordingly, the brush 100 shows a significant elastic bending deformation so that the first limit part 113 and the second limit part 132 are pressed against each other. The significant elastic bending deformation of the brush 100 generates feedbacks that reminds and stops the user applying the improper force in order to prevent from damaging the teeth and the gums. The types of the feedbacks are a force, a sound, a deformation, or combinations thereof. For example, when the elastic plate is deformed, the user feels the sudden change of the force feedback, the noise of the sound feedback and the inconvenient of using the bending tooth brush as deformation feedback.

When a force stronger than the first critical force is applied to the brush head 110 during the tooth brushing, the elastic plate 120 is bent with an enclosed angle α formed between the extension line of the brush head 110 and the extension line of the handle 130. The end portion of the first limit part 113 extending toward the second limit part 132 and the second limit part 132 are pressed against each other so that to stop the brush head 110 continuously bending relative to the handle 130 and avoids over bending of the elastic plate 120 which generates the unrecoverable plastic deformation. In addition, when the first limit part 113 and the second limit part 132 are pressed against each other, a user is able to apply stronger force to the brush head 110 to clean certain dirty parts of the teeth (e.g., the residue between his/her teeth) without over deformation and loosing the function of tooth brushing.

In order to reduce the deviation of the critical force causing bending of the elastic plate 120 each time, two notches 1231 are formed on the corresponding location of the two straight sides 123 of the elastic plate 120, respectively, so as to fix the bending line of bending deformation at a fixed location on the elastic plate 120. The shape of the notches on the straight sides 123 of the elastic plate 120, for example, is triangle, arc shaped or rectangle. The location of the notches 1231 are at the mid point of the straight side 123 of the elastic plate 120, respectively. However, the disclosure is not limited to the shapes and the locations of the notches.

In addition, the magnitude of the critical elastic force of the elastic plate 120 can be adjusted through the length, the width, the thickness, the curvature of the arc and the composition of the elastic plate. The wider, the more curved, the thicker and the larger elasticity of the elastic plate 120 all cause the stronger critical elastic force of the elastic plate 120, and vice versa. In the first embodiment of the present disclosure, the elastic plate 120 is a rectangle steel plate. However, the disclosure is not limited to the shape of the elastic plate and the composition of the elastic plate. For example, the shape of the elastic plate is trapezoid, and the composition of the elastic plate is a polymer with high elasticity, a metal, or combinations thereof. Furthermore, the two straight sides 123 of the elastic plate 120 are polished to form circular surfaces in order to prevent sharp edges thereof.

Please refer to FIG. 4 to FIG. 6B, the following description is a second embodiment of the present disclosure. FIG. 4 is a schematic perspective view of a brush according to the second embodiment of the present disclosure. FIG. 5 is an exploded view of the brush according to the second embodiment of the present disclosure. FIG. 6A is a cross-sectional view of the brush according to the second embodiment of the present disclosure. FIG. 6B is a cross-sectional view of an elastic plate of the brush along a line 6B-6B in FIG. 6A according to the second embodiment of the present disclosure.

The second embodiment of the present disclosure in FIG. 4 to FIG. 6B is similar to the first embodiment of the present disclosure in FIG. 1 to FIG. 3B. Therefore, the explanations of the operations about the same structure of the first embodiment and the second embodiment of the present disclosure are not repeated here.

The second embodiment of the present disclosure discloses a brush 200 comprising a brush head 210, an elastic plate 220, a handle 230 and a flexible exterior component 240. The brush head 210 comprises a bristle seat 211, a plurality of bristles 212 and a first limit part 213. The bristle seat 211 has a front surface 2111, a back surface 2112 and two side surfaces 2113. The front surface 2111 and the back surface 2112 are opposite to each other. The two side surfaces 2113 are opposite to each other and located between the front surface 2111 and the back surface 2112. The plurality of bristles 212 is located on the front surface 2111 of the bristle seat 211. The first limit part 213 is located on the back surface 2112 of the bristle seat 211. The bristle seat 211, the plurality of bristles 212 and the first limit part 213 are made of polymer. However, the disclosure is not limited to the composition of the bristle seat, the plurality of bristles and the first limit part.

The elastic plate 220 is a rectangle elastic plate with curved shape. However, the disclosure is not limited to the planar shape of the elastic plate. Moreover, the elastic plate 220 has a convex 224, a concave 225, a first arc side 221, a second arc side 222 and two straight sides 223. The convex 224 and the concave 225 are opposite to each other. The first arc side 221 and the second arc side 222 are opposite to each other. The two straight sides 223 are opposite to each other and located between the first arc side 221 and the second arc side 222. The direction of the connecting line between the midpoint of the first arc side 221 and the midpoint of the second arc side 222 is parallel to the direction of the connecting line between the brush head 210 and the handle 230. The first arc side 221 of the elastic plate 220 is connected to the bristle seat 211. The concave 225 of the elastic plate 220 and the front surface 2111 of the bristle seat 211 are facing the same direction.

The handle 230 comprises a grip 231 and a second limit part 232. One end of the grip 231 is connected to the second arc side 222 of the elastic plate 220. The second limit part 232 is located on a side surface of the grip 231 which is facing the same direction with the convex 224 of the elastic plate 220. The composition of the grip 231 and the second limit part 232 are polymer. However, the disclosure is not limited to the composition of the grip and the second limit part.

The first limit part 213 is a rib, and the second limit part 232 is a block. However, the disclosure is not limited to the form of the first limit part and the second limit part. The first limit part 213 extends from the bristle seat 211 toward the second limit part 232. In other embodiment of the present disclosure, the first limit part and the second limit part are a rib and a blocking plane, a block and a rib, or a blocking plane and a rib, respectively.

The elastic plate 220 is surrounded by the flexible exterior component 240 so that the convex 224, the concave 225 and the two straight sides 223 of the elastic plate 220 cannot be contacted by the user. The flexible exterior component 240 is made of polymer.

However, the disclosure is not limited to the composition of the flexible exterior component.

Please refer to FIG. 7 to FIG. 9C; the following descriptions refer to a third embodiment of the present disclosure. FIG. 7 is a schematic perspective view of a brush according to the third embodiment of the present disclosure. FIG. 8 is an exploded view of the brush according to the third embodiment of the present disclosure. FIG. 9A to FIG. 9C are cross-sectional views of the brush according to the third embodiment of the present disclosure.

The third embodiment of the present disclosure in FIG. 7 to FIG. 9C is similar to the first embodiment of the present disclosure in FIG. 1 to FIG. 3B. Therefore, the explanations of the operations about the same structure of the first embodiment and the third embodiment of the present disclosure are not repeated hereinafter.

The third embodiment of the present disclosure discloses a brush 300 comprises a brush head 310, an elastic plate 320, a handle 330 and two covering components 350. The brush head 310 comprises a bristle seat 311, a plurality of bristles 312 and a first limit part 313. The bristle seat 311 has a front surface 3111, a back surface 3112 and two side surfaces 3113. The front surface 3111 and the back surface 3112 are opposite to each other. The two side surfaces 3113 are opposite to each other and located between the front surface 3111 and the back surface 3112. The plurality of bristles 312 is located on the front surface 3111 of the bristle seat 311. The first limit part 313 is located on the back surface 3112 of the bristle seat 311. The bristle seat 311, the plurality of bristles 312 and the first limit part 313 are made of polymer. However, the disclosure is not limited to the composition of the bristle seat, the plurality of bristles and the first limit part.

The elastic plate 320 is a rectangle elastic plate with curved shape. However, the disclosure is not limited to the planar shape of the elastic plate. Moreover, the elastic plate 320 has a convex 324, a concave 325, a first arc side 321, a second arc side 322 and two straight sides 323. The convex 324 and the concave 325 are opposite to each other. The first arc side 321 and the second arc side 322 are opposite to each other. The two straight sides 323 are opposite to each other and located between the first arc side 321 and the second arc side 322. The direction of the connecting line between the midpoint of the first arc side 321 and the midpoint of the second arc side 322 is parallel to the direction of the connecting line between the brush head 310 and the handle 330. The first arc side 321 of the elastic plate 320 is connected to the bristle seat 311. The concave 325 of the elastic plate 320 and the front surface 3111 of the bristle seat 311 are facing the same direction.

The handle 330 comprises a grip 331, a second limit part 332 and a third limit part 333. One end of the grip 331 is connected to the second arc side 322 of the elastic plate 320. The second limit part 332 is located on a side surface of the grip 331 which is facing the same direction with the convex 324 of the elastic plate 320. The third limit part 333 is located on a side surface of the grip 331 which is facing the same direction with the concave 325 of the elastic plate 320. The grip 331, the second limit part 332 and the third limit part 333 are made of polymer. However, the disclosure is not limited to the composition of the grip and the second limit part.

In this embodiment, the first limit part 313 is located at the back surface 3112 of the bristle seat 311. The first limit part 313 comprises a rib 3131 and a loop 3132. The rib 3131 extends from the bristle seat 311 toward the second limit part 332. However, the disclosure is not limited to the location of the first limit part. In other embodiment, the first limit part is located at the front surface of the bristle seat and extends from the bristle seat toward the third limit part. The loop 3132 is located at an end of the rib 3131 which is near to the second limit part 332, and the elastic plate 320 is surrounded by the loop 3132. The second limit part 332 is a block, and the third limit part 333 is a depression. However, the disclosure is not limited to the shape and configuration of the first limit part, the second limit part and the third limit part. In other embodiment of the present disclosure, the first limit part, the second limit part and the third limit part are paired by combining a rib with a loop, a blocking plane, a block or a depression. For example, both the second limit part and the third limit part are blocks, or both the second limit part and the third limit part are depressions.

Two covering components 350 are located at the two side surface 3113 of the bristle seat 311, respectively, and extend toward the handle 310. The elastic plate 320 is located between the two covering components 350 with the two straight sides 323 of the elastic plate 320 covered by the two covering components 350 so that the two straight sides 323 cannot be contacted by the user. The two covering components 350 are made of polymer but not limitative of the present disclosure.

When the user is brushing teeth, the operations of the brush head 310, elastic plate 320, handle 330, first limit part 313 and second limit part 332 shown in FIG. 9A and FIG. 9B are similar to the first embodiment of the present disclosure shown in FIG. 3A and FIG. 3B. Therefore, the explanations of the operations about the same structure of the first embodiment and the third embodiment of the present disclosure are not repeated hereinafter.

As shown in FIG. 9C, when a second force F2 with a direction opposite to the first force F1 is applied to the brush head 310, the brush head 310 is backward-bent relative to the handle 330. Assuming that the second force F2 is applied to the location of the back surface 3112 of the brush head 310 which is corresponding to the center point of the plurality of bristles 312, the second force F2 takes the center point of the elastic plate 320 as the fulcrum and generates a pressing torque relative to the handle 330, and the elastic force of the elastic plate 320 takes the center point of the elastic plate 320 as the fulcrum and generates a resisting torque relative to the handle 330. When the applied force is fixed, the magnitude of the pressing torque is proportional to the distance between the center point of the plurality of bristles 312 and the center point of the elastic plate 320, and the magnitude of the resisting torque is proportional to half of the length of the elastic plate 320 (the distance between the arc side of the elastic plate 320 and the center point of the elastic plate 320). The second force F2 applied to the brush head 310 which has a magnitude equals a maximum magnitude of the elastic force provided by the elastic plate 320 as the reactive force is defined as the second critical force.

The curved structure of the elastic plate 120 provides higher anti-bending ability than the plane structure of the elastic plate. Therefore, when the second force F2 is smaller than or equal to the second critical force, the pressing torque generated by the second force F2 equals to the resisting torque generated by the elastic force of the elastic plate 320. The elastic plate 320 with the curved structure is at a trace backward-bending state which the backward-bending deformation of the elastic plate 320 is negligible. However, once the second force F2 is stronger than the second critical force, the resisting torque generated by the elastic force of the elastic plate 320 is smaller than the pressing torque generated by the second force F2. The curved structure of the elastic plate 320 collapses and looses high anti-bending ability. Therefore, the elastic plate 320 with the curved structure is at a collapsed backward-bending state which the backward-bending deformation of the elastic plate 320 is significant.

For example, when a user stores the tooth brush normally, the second force F2 is weaker than the second critical force so that the curved structure of the elastic plate 320 is at the trace backward-bending state which the backward-bending deformation of the elastic plate 320 is negligible. Once the user uses improper way to store the tooth brush, which is like packing the tooth brush in a jam-packed bag, the second force F2 applied to the brush head 310 is stronger than the second critical force so that the elastic plate 320 is at the collapsed backward-bending state which the backward-bending deformation of the elastic plate 320 is significant. Accordingly, the brush 300 shows a significant elastic backward-bending deformation so that the first limit part 313 and the third limit part 333 are pressed against each other. If the elastic plate 320 is over backward-bent and generates an unrecoverable plastic deformation, the brush 300 looses the ability to help the user to control the brushing stress.

When the second force F2 applied to the brush head 310 is stronger than the second critical force, the elastic plate 320 is bent with an enclosed angle β formed between the extension line of the brush head 310 and the extension line of the handle 330. The loop 3132 of the first limit part 313, which is surrounding the elastic plate 320, and the third limit part 333 are pressed against each other so as to stop the brush head 110 from continuously bending relative to the handle 130 and also avoid over bending of the elastic plate 320 which generates the unrecoverable plastic deformation. The unrecoverable plastic deformation causes the tooth brush to loose the ability of helping the user to control the brushing stress.

In addition, the brush head 310 further comprises a tongue-coating scraper located at the back surface 3112 of the bristle seat 311. When the user is cleaning the tongue-coating by the tongue-coating scraper, a second force F2 is applied to the brush head 310. When the second force F2 applied to the brush head 310 is stronger than the second critical force, the elastic plate 320 is at the collapsed backward-bending state. Due to the first limit part 313 and the third limit part 333 being pressed against each other, the user is able to apply stronger force to the brush head 310 to clean the tongue-coating without over deformation and loosing the function of tooth brushing.

In the third embodiment of the present disclosure, the two straight sides 323 of the elastic plate 320 are covered by the two covering components 350 so that the elastic plate 320 cannot be contacted by the user. However, the disclosure is not limited to the form of the covering component of the elastic plate. In one embodiment which is similar to the first embodiment of the present disclosure, the brush comprises a brush head, an elastic plate, a handle, a first limit part, a second limit part, a flexible exterior component and a third limit part. The concave, the convex and the two straight side of the elastic plate are surrounded by the flexible exterior component so that the elastic plate cannot be contacted by the user. Since the first limit part and the second limit part are pressed against each other or the first limit part and the third limit part are pressed against each other, the over bending of the elastic plate and the generation of the unrecoverable plastic deformation of the brush are avoided.

Please refer to FIG. 10A, FIG. 10B, FIG. 10C and Table 1. FIG. 10A to FIG. 10C are front side views of the brushes according to the fourth embodiment to the sixth embodiment of the present disclosure. Table 1 is an experiment data table comparing the numbers of the bristles, the length of the brush head, the length of the elastic plate, the critical elastic force of the elastic plate and other parameters of the other embodiments in the present disclosure. The experiment data in table 1 is fulfilled under two hypotheses. The first hypothesis is that the total stress applied to two teeth by 24 bundles of bristles is 150 grams-weight, and the elastic plate (U-shaped steel plate) has a fixed length. The second hypothesis is that the length between the center point of the bristles region and the center point of the elastic plate is equal to the sum of the length between the center point of the bristles region and the end portion of the bristle seat connecting the elastic plate and the length between the arc side and the center point of the elastic plate.

The brushes 400, 500, 600 in a fourth embodiment to a sixth embodiment of present disclosure have 17 bundles, 28 bundles and 40 bundles of bristles located at the brush head 410, 510 and 610, respectively. However, the disclosure is not limited to the number of the bundle of the bristles. Other embodiments with different number of bristles of the present disclosure are shown in Table 1. The stress applied to the tooth by a bundle of bristles on the brush is fixed. Therefore, the strength applied to the brush head 410,510 and 610 by the teeth increases with the increase of number of bristles contacted by the teeth. Generally, two teeth contact all the bristles on the brush head at once. Due to the tooth size and the mouth size of adults and children are different, the user is advised to choose stress control brush with different critical force coordinated to the user's tooth size and mouth size. The elastic plates with different sizes and different materials are chosen to coordinate with the number of the bristles on the brush head with different size during the designing stage. Therefore, no improper brushing stress is applied to the teeth of different users when using the stress control brush. The fourth through the sixth embodiments of the present disclosure are similar to the first through the third embodiments of the present disclosure. Therefore, the explanations about the operations of the same structures of the fourth embodiment to the sixth embodiment of the present disclosure are not repeated here.

Please refer to FIG. 11A to FIG. 11B and Table 1, FIG. 11A to FIG. 11B are cross-sectional views of the brushes according to a seventh embodiment to an eighth embodiment of the present disclosure.

The brushes 700 and 800 in the seventh embodiment and the eighth embodiment of present disclosure have a length L1 and a length L2 between the center point of the bristles region and the center point of the elastic plate, respectively. However, the disclosure is not limited to the length between the center point of the bristles region and the center point of the elastic plate. Other embodiments with different lengths between the center point of the bristles region and the center point of the elastic plate of the present disclosure are shown in Table 1. When a user is brushing his/her teeth, a first force F1 takes the center point of the elastic plate as the fulcrum and generates a pressing torque relative to the handle, and the elastic force of the elastic plate takes the center point of the elastic plate as the fulcrum and generates a resisting torque relative to the handle. When the force applied is fixed, the magnitude of the pressing torque is proportional to the distance between the center point of the plurality of bristles and the center point of the elastic plate. The magnitude of the resisting torque is proportional to half of the length of the elastic plate (the distance between the arc side of the elastic plate and the center point of the elastic plate). The elastic plates with different sizes and different materials are chosen to coordinate with the brush heads with different lengths during the designing stage. Therefore, no improper brushing stress is applied to the teeth when the user using the stress control brushes with different brush head lengths. The seventh embodiment and the eighth embodiment of the present disclosure are similar to the first embodiment to the third embodiment of the present disclosure. Therefore, the explanations about operations of the same structures of the seventh embodiment and the eighth embodiment of the present disclosure are not repeated here.

TABLE 1 Size SS S1 S2 M L1 L2 Number of bristle 12 16 20 24 28 32 bundles contact two teeth (bundles) Applied stress per 0.00625 0.00625 0.00625 0.00625 0.00625 0.00625 bundle of bristle (kg) Total stress applied 0.075 0.1 0.125 0.15 0.175 0.2 to two teeth (kgw) Distance between 0.05 0.05 0.05 0.065 0.065 0.065 center point of bristles and center point of elastic plate (m) Pressing 0.00375 0.005 0.00625 0.00975 0.011375 0.013 torque (kg · m) Length of elastic 0.008 0.008 0.008 0.008 0.008 0.008 plate (m) Bending position of 0.004 0.004 0.004 0.004 0.004 0.004 elastic plate (m) Elastic force of 0.9375 1.25 1.5625 2.4375 2.84375 3.25 elastic plate (kg) Resisting 0.00375 0.005 0.00624 0.00975 0.011375 0.013 torque (kg · m)

According to the stress control brush of the present disclosure, the curved structure of the elastic plate provides higher anti-bending ability than the plane structure of the elastic plate. When a user applies a proper force for tooth brushing, the first force F1 is weaker than the first critical force so that the elastic plate is at the trace bending state which the bending deformation of the elastic plate is negligible. Once the user applies an improper force, which can damage the teeth and the gums while tooth brushing, the first force F1 is stronger than the first critical force so that the elastic plate is at the collapsed bending state which the bending deformation of the elastic plate is significant. The significant elastic bending deformation of the brush generates feedbacks, for example, the sudden force changing of the force feedback and the noise of the sound feedback that reminds and stops the user using improper brushing force which causes teeth and gums damage.

Moreover, when a brushing force which is stronger than the first critical force is applied to the stress control brush of the present disclosure, the elastic plate is bent so that the end of the first limit part is pressed against the second limit part, which stops the elastic plate bending continuously relative to the handle. Therefore, the situation of over bending of the elastic plate which leads to the unrecoverable plastic deformation and the damaging of stress control function is avoided by the first limit part and the second limit part.

In addition, when using the stress control brush, the force is transferred from the brush head to the elastic plate connected to the brush head directly. The force dissipation during the force transferring is reduced. Therefore, the forces applied to the brush head and transferred to the elastic plate and to trigger the bending of the elastic plate are consistent. Furthermore, two notches which are formed on the corresponding location of the two straight side of the elastic plate, respectively, restrict the bending line of bending deformation at a fixed position and also help to maintain the forces causing the elastic plate to be bent consistently.

In addition, when the first limit part and the second limit part of the stress control brush in the present disclosure are pressed against each other, user can applied stronger force to the brush head to clean the particularly dirty parts of the teeth (e.g., the residue between teeth) without over deformation of the brush.

In addition, the first limit part and the second limit part of the brush in the present disclosure are located at the outside of the brush head and the outside of the handle, respectively. Therefore, gaps are diminished on the brush so that less residue is left in the brush, and the brush is easy to be cleaned and dried so that the possibility of growing bacteria on the brush is decreased. 

What is claimed is:
 1. A stress control brush, comprises: a brush head comprising a bristle seat and a first limit part; a handle comprising a grip and a second limit part; and an elastic plate interconnecting the brush head and the handle, the elastic plate with a curved structure having an unbending state and a collapsed bending state; wherein, the first limit part and the second limit part are pressed against each other so as to restrict a bending curvature of the elastic plate at the collapsed bending state.
 2. The stress control brush of claim 1, wherein the first limit part is a rib, the second limit part is a block, the rib extends along a direction from the brush head toward the block.
 3. The stress control brush of claim 1, further comprising a flexible exterior component made from polymer, the elastic plate being surrounded by the flexible exterior component.
 4. The stress control brush of claim 1, wherein the elastic plate further has a first arc side and a second arc side that are opposite to each other, and two straight sides that are opposite to each other, the two straight sides are located between the first arc side and the second arc side, and each of the two straight sides has a notch.
 5. The stress control brush of claim 1, wherein the brush head further comprises a plurality of bristles, the bristle seat has a front surface and a back surface that are opposite to each other, the plurality of bristles are set on the front surface, when a first force greater than a first critical force is applied to the brush head along a direction toward the front surface, the elastic plate is at the collapsed bending state.
 6. The stress control brush of claim 5, further comprising two covering components, the bristle seat further having two side surfaces located between the front surface and the back surface that are opposite to each other, the two covering components located on the two side surfaces of the bristle seat and extending toward the handle, respectively, the elastic plate located between the two covering components, the elastic plate having a first arc side, a second arc side and two straight sides, the first arc side and the second arc side being opposite to each other, the two straight sides located between the first arc side and the second arc side that are opposite to each other, the two straight sides of the elastic plate covered by the two covering components, respectively.
 7. The stress control brush of claim 5, wherein the first limit part is located on the back surface of the bristle seat.
 8. The stress control brush of claim 5, wherein the handle further comprises a third limit part, the second limit part and the third limit part are located on two side surfaces of the grip that are opposite to each other, when a second force greater than a second critical force is applied to the brush head along a direction toward the back surface of the bristle seat, the elastic plate is at a collapsed backward-bending state, and the first limit part and the third limit part are pressed against each other so as to restrict the bending curvature of the elastic plate; wherein the first critical force is greater than the second critical force.
 9. The stress control brush of claim 8, wherein the first limit part is located on the front surface of the bristle seat.
 10. The stress control brush of claim 8, wherein the first limit part comprises a rib and a loop, the second limit part is a block, and the third limit part is a depression, the rib extends along a direction from the brush head toward the block, the loop is located on a terminal of the rib close to the block and surrounding the elastic plate.
 11. A stress control brush, comprising: a brush head comprising a bristle seat; a handle comprising a grip; and an elastic plate connecting the brush head and the handle, the elastic plate with a curved structure having an unbending state and a collapsed bending state, the elastic plate generating a feedback at the collapsed bending state.
 12. The stress control brush of claim 11, wherein a type of the feedback is a force, a sound, a deformation, or a combination thereof.
 13. The stress control brush of claim 11, wherein the brush head further comprises a first limit part, the handle further comprises a second limit part, and a bending curvature of the elastic plate is restricted at the collapsed bending state. 